He was born at Birthorpe in Lincolnshire, eldest son of John de Birthorpe, Lord of the Manor of Birthorpe. He is said to have qualified as a lawyer, and is known to have acted as his father's attorney. He succeeded to the family estates before 1312. He has been described as a "forceful and dextrous" speaker, but, like many medieval landowners, he was quite capable of resorting to violence to achieve his ends.
The raid on Sempringham Priory and its consequences
In 1312 the neighbourhood of Birthorpe was plagued by a series of raids and counter-raids, involving John de Camelton, the Prior of Sempringham on the one hand, and Roger and his brothers, assisted by Sir Geoffrey Luttrell and other neighbours, on the other. In July 1312 the Prior made a formal complaint to the Crown that these men had invaded the priory, broken down its doors, carried off goods to the value of £500 and assaulted several of the monks. A commission of oyer and terminer was set up to investigate the complaint, and in due course it found Roger guilty of trespass: he was fined 500 marks, a sum which Roger, whose income was about £40 a year, could not possibly pay. Presumably because he defaulted on the payment, he was imprisoned in Lincoln Castle, from which he escaped. His estate at Birthorpe was forfeited to the Crown, and regranted to Henry de Beaumont: Roger fled to Ireland and was outlawed. A second commission, set up to investigate Roger's counter-claim that the Prior had unlawfully seized some of his cattle, was abandoned almost at once.
Roger's defence
According to Roger's later petition, he was the innocent party in the conflict, although he admitted to having impounded some cattle belonging to the Prior. By his account he and his companions fully intended to reach "a good accord" with the Prior, who however would not receive them; and then "conceiving a malicious plan, he had the doors cut down by the men of his household", and raised the hue and cry against Roger. Roger pleaded that the Prior's false accusation had led to his wrongful conviction, and that "for the great malice of the said Prior, Roger dared not remain in England but crossed into Ireland", and subsequently the Prior put so much pressure on the authorities that Roger was declared an outlaw. Roger accordingly pleaded for the restitution of his lands.
In Ireland
While Roger may well have been minimizing his own part in the Sempringham raid, his account of subsequent events is probably truthful enough. He arrived in Ireland in 1313, very likely to seek the assistance of thw family of his friend Geoffrey Luttrell, who had recently become influential there. He also acquired powerful patrons in the FitzGerald family, headed by John FitzGerald, 1st Earl of Kildare. In 1316, Kildare and other "magnates of Ireland" procured a royal pardon for him and thereafter his rise to power was rapid. In 1318 he became a justice in the court of the Justiciar of Ireland, and subsequently a justice of the Court of Common Pleas. In 1327, the same year he petitioned the King for the restitution of his lands, he became Chief Baron of the Irish Exchequer.
Last years
His plea for the restitution of his property was not successful in the short run, but he returned to Lincolnshire about 1330. He seems to have been restored to favour, and he sat on at least two commissions of oyer and terminer. There is a suggestion that he had regained possession of Birthorpe by 1344, although it passed to the Deyncourt family soon afterwards, which may be evidence that neither Roger nor his brothers had any issue.
